U.S. patent number 4,871,315 [Application Number 07/175,209] was granted by the patent office on 1989-10-03 for ribbon cable connector.
This patent grant is currently assigned to Burndy Corporation. Invention is credited to Rocco Noschese.
United States Patent |
4,871,315 |
Noschese |
October 3, 1989 |
Ribbon cable connector
Abstract
An electrical connector terminates ribbon cable intended for
electrical connection to a PCB. The connector presents multiple
contacts from the ribbon cable for engagement with mating terminals
on the PCB as the connector is first moved into position for
mounting on the PCB. Guide pins on the connector are slidably
received in associated guide holes in the PCB to assure that each
contact is properly positioned to engage its mating terminal.
Thereupon, fasteners are tightened for firmly securing the
connector to the PCB and, in the process, the contacts are moved
relative to their mating terminals in a wiping action while still
in engagement with them. Relative movement between the contacts and
the terminals ceases when the fasteners are fully tightened.
Individual groups of contacts are independently biased into
engagement with the terminals with a predetermined minimum of
force. The ends of the cable are slitted in the contact region to
insure that one group of contacts is independent from its
neighboring groups of contacts, thereby maximizing positive
engagement between the contacts and their mating terminals.
Inventors: |
Noschese; Rocco (Wilton,
CT) |
Assignee: |
Burndy Corporation (Norwalk,
CT)
|
Family
ID: |
22639391 |
Appl.
No.: |
07/175,209 |
Filed: |
March 30, 1988 |
Current U.S.
Class: |
439/67; 439/77;
439/493; 439/329; 439/499 |
Current CPC
Class: |
H01R
12/79 (20130101) |
Current International
Class: |
H01R
12/24 (20060101); H01R 12/00 (20060101); H01R
009/09 () |
Field of
Search: |
;439/67,492-494,498,499,329,77 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bradley; P. Austin
Attorney, Agent or Firm: Perman & Green
Claims
What is claimed is:
1. An electrical connector assembly comprising:
a first component having at least one electrically conductive
terminal thereon;
a second component having at least one contact thereon engageable
with said terminal and being movable between an initial position
and a final position while said contact remains engaged with said
terminal, said second component including resilient means biasing
said contact toward engagement with said terminal.
2. An electrical connector assembly as set forth in claim 1
wherein said first component is a printed circuit board having a
plurality of said terminals thereon;
wherein said second component is a connector having a plurality of
said contacts; and
wherein each of said contacts is engageable with an associated one
of said terminals.
3. An electrical connector assembly as set forth in claim 1
wherein said first component has a plurality of aligned equally
spaced terminals thereon; and
wherein said second component has a plurality of similarly aligned
equally spaced contacts thereon, one of said contacts being
engageable with a mating one of said terminals.
4. An electrical connector assembly as set forth in claim 1
wherein said first component has at least two rows each of a
plurality of aligned equally spaced terminals thereon; and
whereon said second component has at least two rows each of a
plurality of similarly aligned equally spaced contacts thereon, one
of said contacts being engageable with a mating one of said
terminals.
5. An electrical connector assembly as set forth in claim 1
wherein said resilient means is a metal spring.
6. An electrical connector assembly as set forth in claim 1
wherein said second component includes:
a housing having a first cam surface lying in a plane angularly
disposed in relation to a plane of engagement of said terminal and
said contact; and
an actuating block mounted on said first component engaged with
said first cam surface for moving said second component between
said initial position and said final position, said actuating block
being movable between a withdrawn position distant from said first
component whereat said housing is in said initial position and an
advanced position proximate to said first component whereat said
housing is in said final position.
7. An electrical connector assembly as set forth in claim 6.
wherein said first cam surface is planar; and
wherein said actuating block has a second cam surface slidably
engaged with said first cam surface.
8. An electrical connector assembly as set forth in claim 6,
including:
fastener means for mounting said actuating block on said first
component;
said resilient means biasing said actuating block toward said
withdrawn position.
9. An electrical connector assembly as set forth in claim 8
including:
mutually cooperative positioning means on said actuating block and
on said first component for maintaining alignment of said terminal
and said contact as said second component moves between said
initial and final positions.
10. An electrical connector assembly as set forth in claim 9
wherein said mutually cooperative positioning means include:
a pair of spaced apart, parallel, outwardly projecting alignment
pins on said actuating block slidably engageable with a mating pair
of holes in said first component.
11. A cable holder subassembly for terminating ribbon cable
including a plurality of side by side cable strips, each cable
strip having at least a pair of longitudinally spaced outwardly
projecting contacts thereon, said subassembly comprising:
a cable holder block including:
an elongated main body having first and second opposed sidewalls
and a laterally extending ridge having an extreme surface distant
from said main body and defining a pair of opposed laterally
extending recesses; and
a plurality of parallel, spaced apart ribs in each of the recesses
and integral with said main body and said ridge thereby defining a
plurality of side by side slots; and
a cable spring array including:
a laterally extending elongated spine fixed to said extreme surface
of said ridge;
a plurality of pairs of spring members integral with said spine at
spaced locations along the length thereof, individual members of
each said spring pair extending in opposite directions from said
spine, each of said individual spring members being bowed and
snugly received in an associated one of the slots of said holder
block and terminating at a free end proximate to, but spaced from,
said spine;
thereby enabling the cable strips to be drawn across said first
sidewall, then around said spring array such that each cable strip
is aligned with an associated pair of said spring elements, then
across said second sidewall, the cable being fixed, together with
said cable spring array, to said extreme surface of said ridge,
said free ends of each of said spring members being aligned with an
associated contact on an associated cable strip so as to bias the
contact in a direction away from said holder block.
12. A cable holder subassembly as set forth in claim 11.
wherein said holder block has a laterally extending retainer slot
in said second sidewall adapted to receive the free end of each of
the cable strips; and including:
a resilient retainer member fittingly receivable in said slot and
engageable with the terminal end of each of the cable strips to
firmly secure the cable strips to said holder block.
13. A cable holder subassembly as set forth in claim 11,
including:
retainer means for fixing the terminal end of each of the cable
strips to said holder block.
14. A cable holder subassembly as set forth in claim 11,
including:
a pair of end plates at opposed ends of said main body and integral
therewith, said end plates lying in parallel planes transverse to
said main body and being engageable with a housing for supporting
said subassembly thereon.
15. A cable holder subassembly as set forth in claim 11.
wherein said first sidewall has a rounded surface having a
generally moderate radius of curvature in the direction in which
the ribbon cable extends to enable the ribbon cable to change
direction while in contiguous engagement with said holder block
without causing harm thereto.
16. A cable holder subassembly as set forth in claim 11.
wherein said cable spring array is composed of spring metal.
17. A cable holder subassembly comprising:
ribbon cable to be terminated including:
a plurality of side by side cable strips, each of said cable strips
extending to a tip end and having at least a pair of longitudinally
spaced outwardly projecting contacts thereon proximate to said
terminal end;
a cable holder block including:
an elongated main body having first and second opposed sidewalls
and a laterally extending ridge having an extreme surface distant
from said main body and defining a pair of opposed laterally
extending recesses; and
a plurality of parallel, spaced apart ribs in each of the recesses
and integral with said main body and said ridge thereby defining a
plurality of side by side slots; and
a cable spring array including:
a laterally extending elongated spine fixed to said extreme surface
of said ridge;
a plurality of pairs of spring members integral with said spine at
spaced locations along the length thereof, individual members of
each said spring pair extending in opposite directions from said
spine, each of said individual spring members being bowed and
snugly received in an associated one of the slots of said holder
block and terminating at a free end proximate to, but spaced from,
said spine;
thereby enabling said cable strips to be drawn across said first
sidewall, then around said spring array such that each of said
cable strips is aligned with an associated pair of said spring
elements, then across said second sidewall, said cable being fixed,
together with said cable spring array, to said extreme surface of
said ridge, said free ends of each of said spring members being
aligned with an associated one of said contacts on an associated
one of said cable strips so as to bias said contact in a direction
away from said holder block.
18. A cable holder subassembly as set forth in claim 17.
wherein said holder block has a laterally extending retainer slot
in said second sidewall adapted to receive said free end of each of
said cable strips; and including:
a resilient retainer member fittingly receivable in said slot and
engageable with said terminal end of each of said cable strips to
firmly secure said cable strips to said holder block.
19. A cable holder subassembly as set forth in claim 17,
including:
retainer means for fixing said terminal end of each of said cable
strips to said holder block.
20. A cable holder subassembly as set forth in claim 17,
including:
a pair of end plates at opposed ends of said main body and integral
therewith, said end plates lying in parallel planes transverse to
said main body and being engageable with a housing for supporting
said subassembly thereon.
21. A cable holder subassembly as set forth in claim 17.
wherein said first sidewall has a rounded surface having a
generally moderate radius of curvature in the direction in which
said ribbon cable extends to enable said ribbon cable to change
direction while in contiguous engagement with said holder block
without causing harm thereto.
22. A cable holder subassembly as set forth in claim 17.
wherein said ribbon cable is formed in a plurality of layers
including an innermost elongate conductor, then successively in
both directions transversely of said conductor, an inner sheath of
dielectric material, a copper shield, and an outer protective
sheath of dielectric material.
23. A cable holder subassembly as set forth in claim 17.
wherein said cable spring array is composed of spring metal.
24. A cable holder subassembly as set forth in claim 17.
wherein said ribbon cable includes an outer protective sheath of
dielectric material, said cable being stripped of said protective
sheath proximate to its terminal end to expose said contacts, each
one of said strips being separated from adjacent ones of said
strips to enable independent relative movement in directions
transverse to the plane of said cable of said contacts on one of
said strips in relation to said contacts on others of said
strips.
25. A cable holder subassembly as set forth in claim 24.
wherein said holder block is composed of a heat deformable plastic
material, said ridge including a plurality of outwardly projecting
laterally spaced mounting pins;
wherein said elongated spine has a plurality of spaced mounting
holes positioned for reception over said mounting pins; and
wherein each of said strips has a mounting hole therein
intermediate said contacts thereon and receivable over an
associated one of said mounting pins; and
wherein said pins are heat deformed to fix said spine and said
strips to said ridge such that all of said contacts lie
substantially in a common plane and are the most prominent portions
of said subassembly in a direction away from said holder block.
26. A subassembly for an electrical connector assembly
comprising:
a housing including a top wall, a front wall, and spaced apart side
walls having opposed surfaces and a plurality of generally
vertically disposed slots in said opposed surfaces at regularly
spaced locations distant from said front wall, said housing being
open at its rear end opposite said front wall;
a plurality of cable holder subassemblies receivable for mounting
in said housing in a fore and aft relationship, respectively, each
of said subassemblies including:
a cable holder block having an elongated main body extending
between a pair of integral end plates lying in parallel planes
transverse to said main body, said end plates having integral key
members projecting outwardly therefrom away from said main body and
being slidingly engageable with the slots in said side walls of
said housing; and
ribbon cable extending from a distant location and terminated on
said holder block, said ribbon cable including a plurality of side
by side cable strips, each of said cable strips having at least a
pair of longitudinally spaced outwardly projecting contacts
thereon, said contacts being biased in a direction away from said
holder block;
each of said cable holder subassemblies being movable from a
distant location into engagement with said housing, said end plates
being slidingly received in the slots in said side walls until said
cable holder subassembly assumes a seated position proximate to
said top wall.
27. A subassembly for an electrical connector assembly as set forth
in claim 26.
wherein each of said main bodies has first and second opposed
sidewalls, said first and second sidewalls of adjoining ones of
said main body being in a contiguous and coextensive relationship
when mounted in said housing; and
wherein said ribbon cable comprises a plurality of individual
cables, one of said individual cables being associated with each of
said cable holder subassemblies, said strips lying generally in
successive contiguous parallel planes at said rear end of said
housing and extending through the open rear end of said
housing.
28. A subassembly for an electrical connector assembly as set forth
in claim 27.
wherein said housing is deformable;
wherein said sidewalls have apertures extending therethrough
communicating with said slots adjacent said top wall; and
wherein said end plates of said holder block have outwardly
projecting tabs on said key members which cause said housing to
deform as said cable holder subassembly advances toward said seated
position and engage with associated apertures in said sidewalls
whereupon said housing returns to its original shape and thereby
retains said cable holder subassembly in said seated position.
29. A subassembly for an electrical connector assembly as set forth
in claim 27.
wherein one of said strips lies contiguous to said top wall;
and
wherein another of said strips has an undersurface which faces away
from said top wall; and including:
a cable clamp engageable with said undersurface and mounted on said
housing for squeezing said plurality of strips into fixed
relationship with said top wall.
30. A subassembly for an electrical connector assembly as set forth
in claim 29, including:
fastener means for joining said cable clamp to said housing.
31. A subassembly for an electrical connector assembly as set forth
in claim 26, comprising:
resilient means on said holder block for biasing said contacts in a
direction away from said holder block.
32. A subassembly for an electrical connector assembly as set forth
in claim 31
wherein said resilient means is a metal spring.
33. A subassembly for an electrical connector assembly as set forth
in claim 31
wherein said holder block includes:
first and second opposed sidewalls on said main body and a
laterally extending ridge thereon having an extreme surface distant
from said main body and defining a pair of opposed laterally
extending recesses; and
a plurality of parallel, spaced apart ribs in each of the
recesses
and integral with said main body and said ridge thereby defining a
plurality of side by side slots; and
wherein said resilient means is a cable spring array including: a
laterally extending elongated spine fixed to said extreme surface
of said ridge;
a plurality of pairs of spring members integral with said spine at
spaced locations along the length thereof, individual members of
each said spring pair extending in opposite directions from said
spine, each of said individual spring members being bowed and
snugly received in an associated one of the slots of said holder
block and terminating at a free end proximate to, but spaced from,
said spine;
thereby enabling said cable strips to be drawn across said first
sidewall, then around said spring array such that each of said
cable strips is aligned with an associated pair of said spring
elements, then across said second sidewall, said cable being fixed,
together with said cable spring array, to said extreme surface of
said ridge, said free ends of each of said spring members being
aligned with an associated one of said contacts on an associated
one of said cable strips so as to bias said contact in a direction
away from said holder block.
34. A cable holder subassembly as set forth in claim 33.
wherein said holder block has a laterally extending retainer slot
in said second sidewall adapted to receive said free end of each of
said cable strips; and including:
a resilient retainer member fittingly receivable in said slot and
engageable with said terminal end of each of said cable strips to
firmly secure said cable strips to said holder block.
35. A cable holder subassembly as set forth in claim 33. wherein
said first sidewall has a rounded surface having a generally
moderate radius of curvature in the direction in which said ribbon
cable extends to enable said ribbon cable to change direction while
in contiguous engagement with said holder block without causing
harm thereto.
36. A cable holder subassembly as set forth in claim 33.
wherein said ribbon cable is formed in a plurality of layers
including an innermost elongate conductor, then successively in
both directions transversely of said conductor, an inner sheath of
dielectric material, a copper shield, and an outer protective
sheath of dielectric material.
37. A cable holder subassembly as set forth in claim 33.
wherein said ribbon cable includes an outer protective sheath of
dielectric material, said protective sheath being removed from said
cable proximate to its tip end to expose said contacts, each one of
said strips being separated from adjacent ones of said strips to
enable independent relative movement in directions transverse to
the plane of said cable of said contacts on one of said strips in
relation to said contacts on others of said strips.
38. A cable holder subassembly as set forth in claim 37.
wherein said holder block is composed of a heat deformable plastic
material, said ridge including a plurality of outwardly projecting
laterally spaced mounting pins;
wherein said elongated spine has a plurality of spaced mounting
holes positioned for reception over said mounting pins; and
wherein each of said strips has a mounting hole therein
intermediate said contacts thereon and receivable over an
associated one of said mounting pins; and
wherein said pins are heat deformed to fix said spine and said
strips to said ridge such that all of said contacts lie
substantially in a common plane and are the most prominent portions
of said subassembly in a direction away from said holder block.
39. An electrical connector for mounting on a first component
having at least one electrically conductive terminal thereon
comprising:
a second component having at least one contact thereon engageable
with the terminal and being movable between an initial position and
a final position while said contact remains engaged with the
terminal, said second component including resilient means biasing
said contact toward engagement with said terminal.
40. An electrical connector assembly as set forth in claim 39.
wherein the first component is a printed circuit board having a
plurality of terminals thereon;
wherein said second component is a connector having a plurality of
said contacts; and
wherein each of said contacts is engageable with an associated one
of the terminals.
41. An electrical connector assembly as set forth in claim 39
wherein said second component has a plurality of aligned equally
spaced contacts thereon, one of said contacts being engageable with
a mating one of a plurality of similarly aligned equally spaced
terminals on the first component.
42. An electrical connector assembly as set forth in claim 39
wherein said second component has at least two rows each of a
plurality of aligned equally spaced contacts thereon, one of said
contacts being engageable with a mating one of a plurality of
similarly aligned and spaced terminals on the first component.
43. An electrical connector assembly as set forth in claim 39.
wherein said resilient means is a metal spring.
44. An electrical connector as set forth in claim 39.
wherein said second component includes:
a housing having a first cam surface lying in a plane angularly
disposed in relation to a plane of engagement of the terminal and
said said contact; and
an actuating block mounted on the first component engaged with said
first cam surface for moving said second component between said
initial position and said final position, said actuating block
being movable between a withdrawn position distant from the first
component whereat said housing is in said initial position and an
advanced position proximate to the first component whereat said
housing is in said final position.
45. An electrical connector assembly as set forth in claim 44.
wherein said first cam surface is planar; and
wherein said actuating block has a second planar cam surface
slidably engaged with said first cam surface.
46. An electrical connector as set forth in claim 44,
including:
fastener means for mounting said actuating block on the first
component;
said resilient means biasing said actuating block toward said
withdrawn position.
47. An electrical connector assembly as set forth in claim 46
including:
mutually cooperative positioning means on said actuating block and
on the first component for maintaining alignment of the terminal an
said contact as said second component moves between said initial
and final positions.
48. An electrical connector assembly as set forth in claim 47.
wherein said mutually cooperative positioning means include: a pair
of spaced apart, parallel, outwardly projecting alignment pins on
said actuating block slidably engageable with a mating pair of
holes in the first component.
49. An electrical connector as set forth in claim 48.
wherein said housing has an upper surface and said first cam
surface thereon is planar;
wherein said actuating block overlies said housing and
includes:
a second planar cam surface slidably engaged with said first cam
surface; and
a terminal surface engaged with said upper surface when said
housing is in said final position.
50. An electrical connector as set forth in claim 49.
wherein said resilient means is positioned between said housing and
said actuating block for biasing said terminal surface away from
said upper surface. pg,58
51. An electrical connector as set forth in claim 50.
wherein said resilient means is a compression spring which is
compressed when said terminal surface is engaged with said upper
surface.
Description
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to an electrical connector assembly
capable of simultaneously connecting, mechanically and
electrically, a plurality of contacts on multiconductor stripline
ribbon cable to mating terminals on a printed circuit board. This
is achieved with a construction assuring electrical paths of
minimized length and a minimal number of electrical interfaces. The
connector assembly provides a wiping action of the cable contacts
relative to mating conductive terminals on the printed circuit
board to thereby achieve an optimum electrical connection. The
invention also maintains a relationship between signal and ground
circuits which is controlled to minimize any disturbance of the
impedance required in the system.
II. Description of the Prior Art
In the past, it has been difficult to achieve uniformity of contact
engagement of ribbon cable with mating terminals on a printed
circuit board (PCB), particularly when the number of mating
contacts and terminals is very large. Often times, the cable is
semi-rigid permitting marginal flexibility, at best, between
adjacent contact leads. As a result, in the event of irregularity
among PCB terminals, there is likely to be an insufficient relative
flexibility among the mating contacts to assure a proper electrical
connection with their mating conductive terminals.
However, even where there is uniformity of contact engagement, it
is not unusual for marginal electrical connections to result
between mating contacts and terminals nonetheless because of
surface contaminants, films, and the like. Furthermore, because of
the high density of the contacts and terminals, it is not generally
possible to clean the respective contacts and terminals prior to
mounting a connector to the PCB. Also, maintaining adequate
impedance control through the disconnectable interface was
heretofore difficult to achieve in a dense pattern and in a short
length.
SUMMARY OF THE INVENTION
The present invention recognizes the problems of prior art
connectors, as just described, and offers a solution to those
problems. To this end, an electrical connector is disclosed which
terminates stripline ribbon cable or microstrip intended for
electrical connection to a PCB. The connector presents multiple
contacts of the ribbon cable for engagement with mating terminals
on the PCB as the connector is first moved into position for
mounting on the PCB. Guide pins on the connector are slidably
received in associated guide holes in the PCB to assure that each
contact is properly positioned to engage its mating terminal.
Thereupon, fasteners are tightened for firmly securing the
connector to the PCB and, in the process, the contacts are moved
relative to their mating terminals in a wiping action while still
in engagement with them. Relative movement between the contacts and
the terminals ceases when the fasteners are fully tightened.
Individual groups of contacts are independently biased into
engagement with the terminals with a predetermined minimum of
force. The ends of the cable are slitted in the contact region to
insure that one group of contacts is independent from its
neighboring groups of contacts, thereby maximizing positive
engagement between the contacts and their mating terminals.
The invention provides a high density connector which assures
connection simultaneously of a large number of contacts from a
plurality of ribbon cables to a similar number of terminals on a
PCB. The contacts are positioned in a housing so as to lie
substantially in a common plane. Similarly, the terminals on the
PCB all lie substantially in a common plane. The housing has a
planar cam surface which is angularly disposed in relation to the
plane of engagement of the contacts and the terminals.
Additionally, an actuating block is mounted onto the PCB by means
of fasteners so as to overlie the housing and is also formed with a
planar cam surface which slidably engages the cam surface on the
housing.
As the actuating block is advanced toward the PCB upon tightening
of the fasteners by means of which it is engaged to the PCB, the
cam surface on the actuating block, causes the housing to move
relative to the PCB. In this manner, the contacts, already in
engagement with the terminals are caused to wipe across the
terminals. When the actuating block reaches a final position at
which it is firmly mounted on the PCB, the fasteners themselves
being completely tightened, each of the contacts will have achieved
a final position as well engaged with its mating terminal. A spring
intermediate the actuating block and the housing serves to bias the
housing in the direction of the PCB and thereby assures firm
engagement between the contacts and their mating terminals. The
wiping action just performed assures that any surface contaminants,
films, or the like on either the contacts or on the terminals or on
both of them will have been removed by frictional action between
them by the time the housing reaches its final position.
By reason of the construction disclosed, the connector can be
readily mounted to a PCB and just as readily dismounted therefrom.
Although the mounting operation is a rapid one, when achieved, the
contacts are firmly and immovably engaged with their mating
terminals.
Other and further features, objects, advantages, and benefits of
the invention will become apparent from the following description
taken in conjunction with the following drawings. It is to be
understood that both the foregoing general description and the
following detailed description are exemplary and explanatory but
are not restrictive of the invention. The accompanying drawings
which are incorporated in, and constitute a part of the invention,
illustrate one embodiment of the invention and, together with a
description, serve to explain the principles of the invention in
general terms. Like numerals refer to like parts throughout.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an electrical connector assembly
illustrating an electrical connector embodying the invention
mounted on a printed circuit board;
FIG. 2 is an exploded view illustrating a pair of electrical
connectors embodying the invention positioned for mounting on
associated printed circuit boards;
FIGS. 3, 4, and 5 illustrate front elevation, bottom plan, and side
elevation views, respectively, of the electrical connector of the
invention;
FIG. 6 is an exploded view of the components comprising a
subassembly of the electrical connector of the invention;
FIG. 7 is a perspective view of one of the components illustrated
in FIG. 6 generally properly aligned with the other components
thereof to illustrate a further step in the fabrication of the
subassembly;
FIG. 8 is a detail perspective view, certain parts being cut away
and shown in section, of the components illustrated in FIG. 6, but
now assembled;
FIG. 9 is a detail top plan view illustrating the end regions of
stripline ribbon cable which is utilized with the electrical
connector of the invention;
FIG. 10 is a detail top plan view illustrating a portion of the
stripline ribbon cable illustrated in FIG. 9;
FIG. 11 is a cross section view taken generally along line 11--11
in FIG. 10;
FIG. 12 is an exploded perspective view illustrating a complete
electrical connector embodying the invention;
FIG. 13 is a side elevation view, primarily in section,
illustrating the components of FIG. 12 in their assembled
condition;
FIGS. 14 and 15 are side elevation views illustrating the
electrical connector in its initial and final positions,
respectively, on a printed circuit board; and
FIGS. 16 and 17 are cross section views of the electrical connector
generally corresponding to FIGS. 14 and 15.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turn now to the drawings and initially to FIGS. 1 and 2 which
illustrate an electrical connector 20 which embodies the present
invention. In FIG. 1, the electrical connector 20 is illustrated as
being already mounted on a printed circuit board (PCB) 22 and, in
FIG. 2, a pair of electrical connectors 20 are illustrated as being
positioned for mounting onto a similar pair of PCBs 22. As seen in
FIGS. 3, 4, and 5, each electrical connector 20 has a plurality of
contacts 24 which are engageable with mating conductive terminals
26 on each PCB 22 in a manner to be described.
As seen in FIG. 6, the electrical connector 20 includes a plurality
of cable holder subassemblies 28 and each such subassembly will now
be described with particular attention to FIGS. 7 and 8. A central
component of each subassembly 28 is a cable holder block 30 which
includes an elongated main body having opposed side walls 32 and 34
and a laterally extending ridge 36. The ridge 36 has an extreme
surface 38 distant from the main body and defines a pair of opposed
laterally extending recesses 40 and 42. A plurality of parallel,
spaced apart ribs 44 in each of the recesses 40, 42 are integral
with the main body of the block 30 and said ridge 36 and thereby
define a plurality of side-by-side slots 45. The holder block 30 is
preferably composed of a heat deformable plastic material and the
ridge 36 includes a plurality of outwardly projecting laterally
spaced mounting pins 46 for a purpose which will be described
subsequently.
With continuing reference to FIGS. 7 and 8, a unitized cable spring
array 48 is provided which is preferably stamped from a suitable
resilient material, spring steel being a preferred material for
strength, consistency of operation, and ease of manufacture. The
spring array 48 includes a laterally extending elongated spine 50
and a plurality of pairs of spring members 52, 54 integral with the
spine and positioned at spaced locations along the length of the
spine. The members 52 and 54 extend in opposite directions from the
spine and each is bowed and snuggly received in an associated one
of the slots 45 of the holder block 30 and terminates at a free end
proximate to, but spaced from the spine. The spine 50 has a
plurality of laterally spaced mounting holes 56 positioned for
reception over the mounting pins 46 for eventual mounting to the
holder block 30 in a manner to be described.
Also comprising a part of the cable holder subassembly 28 is ribbon
cable 58 to be terminated on the holder block 30. The ribbon cable
58 is of the "stripline" variety which is, perhaps, more clearly
illustrated in FIGS. 9, 10, and 11. The ribbon cable 58 includes a
plurality of side-by-side cable strips 60 each of which extends to
a tip end 62. A plurality of longitudinally and laterally spaced
outwardly projecting contacts 24 are formed thereon generally
proximate to, but spaced from, the tip end 62. The ribbon cable 58
includes a suitable outer protective sheath 66 of dielectric
material, but that sheath is removed from the end regions of the
strips 60 to expose the contacts 24. In addition to the outer
sheath 66, the ribbon cable 58 includes a plurality of inner
conductors 68, laterally spaced across the cable, which is
sandwiched between inner sheaths 70 of dielectric material which,
in turn, is sandwiched between sheets of copper shield material 72.
Each cable strip 60 is separated from its neighboring strip along a
cut or slit line 74 enabling independent relative movement of each
strip 60 in directions transverse to the plane of the cable 58.
Also formed in each strip 60 at a location intermediate its opposed
edges and disposed centrally in a longitudinal direction of the
contacts 24 is a mounting hole 76 receivable over an associated one
of the mounting pins 46.
FIG. 6 illustrates the relative positioning of the ribbon cable 58
and the holder block 30 as the cable is about to be mounted
thereon. However, before the cable 58 is actually attached to the
holder block 30, the cable strips 60 are fashioned, as on a
mandrel, into the shape illustrated in FIG. 7. The individual
components illustrated in FIGS. 6 and 7 are then joined together
into the subassembly 28 illustrated in FIG. 8. Specifically, the
spring array 48 is mounted onto the holder block 30 so that the
spine 50 is contiguous with the extreme surface 38 of the ridge 36
with the mounting pins 46 projecting through associated mounting
holes 56 in the spine. Thereafter, the strips 60 of the ribbon
cable 58 are mounted onto the holder block 30 so as to be
contiguous with the spine 50 and, as in the instance of the spring
array 48, with each of the mounting pins 46 projecting through an
associated mounting hole 76 in the cable strips.
At this stage of the assembly, the ribbon cable 58 extends in a
contiguous manner across the sidewall 32. As seen in FIG. 8, the
sidewall 32 has a rounded surface with a generally moderate radius
of curvature to guide the ribbon cable as it advances from a
distant location for termination. This moderate radius of curvature
enables the ribbon cable to change direction while in contiguous
engagement with the holder block 30 without causing harm to the
cable. Thereupon, the cable 58 is drawn around the spring array 48
such that each of the cable strips 60 is aligned with an associated
pair of the spring members 52, 54. The cable strips 60 then advance
across the sidewall 32 and are folded for entry into a laterally
extending retainer slot 78 formed in the sidewall 34. An elongated
resilient retainer member 80 composed of rubber or other
elastimeric material is fittingly received in the slot 78 and
thereby firmly secures the tip ends 62 of the cable strips 60 to
the holder block 30.
The nose end of the cable holder subassembly 28 as now represented
by those portions of the cable strip 60 with the contacts 24
thereon is then advanced toward a heated mandrel (not shown) which
is shaped in a complimentary fashion to assure that the strips 60
assume the arcuate paths as illustrated in FIG. 8. It was
previously mentioned that the holder block 30 is preferably
composed of a heat deformable plastic material. Thus, with the
application of heat simultaneous with the positioning of the
subassembly 28 against the mandrel, the mounting pins 46 are
melted, then resolidified into the form of stake bosses 82 as seen
in FIG. 8. The stake bosses therefore serve the function of rivets
or other suitable fasteners which may be utilized in mounting of
the ribbon cable and of the spring array to the holder block.
In the resulting construction of the cable holder subassembly 28 as
illustrated in FIG. 8, all of the contacts 24 are substantially
coplanar for mating engagement with the terminals 26 on the PCB 22
which are also substantially coplanar. By reason of the
construction according to which the ribbon cable 58 is formed into
a plurality of individual cable strips 60, each contact 24 is
outwardly biased by its own individual spring 52 or 54. In this
manner, the subassembly 28 can be designed such that each
individual contact 24 receives a minimum force of 100 grams
regardless of the dimensional relationship to all of the contacts
adjacent to it. That is, even though a contact 24 may be somewhat
shorter than its neighbors, it is independent of them and will not
adversely effect their ability to contact their mating terminals 26
on the PCB. Thus, the design of the invention assures that each
contact 24 will act independently and thereby compensate for any
height differences which may exist. Also, because of the desire to
assure that each individual contact 24 receives a minimum force of
100 grams, for example, metal springs have been preferably chosen
to achieve this result.
It is recognized that elastomeric springs are capable of performing
in place of the spring members 52, 54. Nonetheless, while the
simplicity of using rubber or other elastomeric material for this
purpose is attractive, the ability of elastomeric materials to
maintain the high forces over a long period of time in a variety of
elevated temperature and other environmental conditions is subject
to question. In contrast, the ability of metal alloys to perform
this function has been proven for environmental conditions which
are considerably more severe than those anticipated in a normal
commercial computer application. It is for these reasons that metal
springs are preferred.
Turn now to FIGS. 12 and 13 which illustrate the manner in which a
plurality of the subassemblies 28 are mounted in a housing 84. The
housing 84 is composed of a moderately deformable plastic material
and includes a top wall 86, a slanted front wall 88 and spaced
apart sidewalls 90 having opposed surfaces and a plurality of
generally vertically disposed slots 92 in the opposed surfaces at
regularly spaced locations proceeding away from the front wall 88.
The housing 84 is open at its rear end opposite the front wall 88.
Each cable holder block 30 extends between a pair of integral end
plates 94 which lie in parallel planes transverse to the main body.
The end plates 94 have integral key members 96 which project
outwardly from the end plates in a direction away from the main
body of the holder block 30. At the upper end of each key member 96
is a further outwardly projecting tab 98.
The holder blocks 30 are so sized and shaped that, as seen in FIG.
12, the key members 96 are slidably engageable with associated
slots 92 in the sidewalls 90 of the housing 84. The sidewalls 90
are further provided with apertures 100 which extend completely
through the sidewalls and communicate with the slot 92 adjacent the
top wall 86. Thus, as a cable holder block 30 is inserted into the
cavity defined by the sidewalls 90, the front wall 88, and the top
wall 86, the tabs 98 cause the sidewalls to deform until the tabs
are coextensive with the apertures 100 and slidably engage the
apertures. This causes the end plates 94 to snap into position
contiguous with the sidewalls 90 as the sidewalls recover their
original shape. As seen in FIG. 12, this occurs three times. That
is, three of the holder blocks 30 are thereby mounted in the
housing 84 with the ribbon cable 58 from each successive
subassembly 28 overlying and being contiguous with the ribbon cable
from the next successive subassembly. This relationship is also
seen in FIG. 13.
While the cooperating tabs 98 and apertures 100 operate to firmly
secure the holder blocks 30 in the housing 84, a further expedient
for this purpose is a cable clamp 102. The cable clamp 102 has a
horizontal plate 104 which extends across and is contiguous with
the undersurface of a lowermost cable 58 as it extends through the
rear opening of the housing 84. A vertical plate 106 bent over from
the horizontal plate 104 engages the sidewall 34 of the rearmost
holder block 30 to further prevent fore and aft movement of the
holder blocks 30 relative to the housing 84. The plate 106 also
guards against loosening of the retainer member 80 mounted in the
rearmost holder block 30. In a similar fashion, the other retainer
members mounted in the other holder blocks are similarly protected
from inadvertent loosening or removal by their neighboring
subassembly 28. Screws 108, or other suitable fasteners, extend
through associated clearance holes 110 formed in the top wall 86
and are threadedly engaged with tapped bosses 112 integral with
outwardly extending ears 114 on the cable clamp 102. When the
screws 108 are fully tightened, the horizontal plate 104 firmly
joins and supports the individual cables 58 against the top wall 86
and the vertical plate 106 prevents fore and aft motion of the
individual holder blocks 30 relative to the housing 84.
With continuing reference to FIGS. 12 and 13, electrical connector
20 is seen to include an actuating block 116 which overlies the
housing 84 and is mounted to the PCB by means of suitable fasteners
118. The PCB 22 may have tapped holes 120 therein as illustrated in
FIG. 1 or may have clearance holes 122 as illustrated in FIG. 14.
In the former instance, the fasteners 118 directly engage the PCB
22 while in the later instance, a mounting block or back plane 124
is provided with a tapped hole 126 for threadedly receiving the
fastener 118. In either event, the actuating block 116 is provided
with a pair of spaced apart, parallel, outwardly projecting
alignment pins 128 which are slidably engageable with a mating pair
of alignment holes 130 formed in the PCB. The fasteners 118 extend
through clearance holes 132 formed in opposed lateral extensions
134 of the actuating block 116.
The actuating block 116 defines a cavity 136 for the slidable
reception of the housing 84. The cavity 136 is defined by a pair of
opposed side surfaces 138, a terminal surface 140, and a planar cam
surface 142 (FIG. 13). A pair of wing members 144 extend in
opposite directions from the front wall 88 of the housing 84 and
are slidably receivable in complementary slanted slots 146 formed
in the side surfaces 138 of the actuating block 116. In a similar
manner, a centrally disposed key 148 is slidably received in a
complementary slot 150 formed in a front wall 152 of the actuating
block 116.
The front wall 88 of the housing 84 also has a planar cam surface
154 which is slidably engageable with the cam surface 142 of the
actuating block 116. As seen in FIG. 13, a pair of laterally spaced
cylindrical recesses 156 are formed in an upper surface 158 of the
top wall 86. Similarly, a pair of spaced cylindrical recesses 160
are formed in the terminal surface 140 of the actuating block 116.
The recesses 156 and 160 are substantially opposed when the housing
84 is received within the cavity 136 of the actuating block 116. A
suitable compression spring 162 has its opposite ends engaged,
respectively, in the recesses 156 and 160 and serves to bias the
housing 84 away from the actuating block 116.
OPERATION
The operation of the invention, just described, will now be
explained with particular reference to FIGS. 14-17. When it is
desired to mount the connector 20 onto the PCB 22, the connector is
positioned relative to the PCB such that the alignment pins 128 are
positioned for reception into the alignment holes 130 of the PCB
(FIG. 14). When this occurs, the contacts 24 on the connector 20
are aligned with their mating terminals 26 on the PCB and the
connector 20 rests lightly on the upper surface of the PCB 22. The
fasteners 118 are initially raised above the tapped holes 126 of
the back plane 124 in the event that that is the mounting
construction employed. Of course, the fasteners 118 would be raised
above the upper surface of the PCB 22 in the alternative situation
in which the construction included tapped holes 120 in the PCB
itself. In either event, the fasteners are then engaged with their
mating tapped holes to begin the process of fixedly mounting the
connector to the PCB.
The springs 162 bias the surfaces 140 and 158 apart. However, when
the fasteners 118 become engaged with their associated tapped holes
126 (FIG. 14) and are tightened, continuing tightening of the
fasteners moves the actuating block 116 downwardly, that is, in the
direction of an arrow 164 and toward the PCB 22. With the cam
surfaces 142 and 154 engaged as seen in FIG. 15, downward movement
of the actuating block 116 in the direction of the arrow 164 causes
rearward movement of the housing 184, that is, in the direction of
an arrow 166 (FIG. 17). In turn, this causes the contacts 24 to
slide in engagement across the terminals 26. Continued tightening
of the fasteners 118 continues to move the actuating block 116 in
the direction of the arrow 164 and the housing 84 in the direction
of the arrow 166 until the final position illustrated in FIG. 17 is
reached. At this point, the surfaces 140 and 158 are engaged and
the spring 162 is fully compressed. When this occurs, the
electrical connector 20 is firmly secured to the PCB 22 and an
optimum electrical connection will have been made between the
contacts 24 and their mating terminals 26.
While a preferred embodiment of the invention has been disclosed in
detail, it should be understood by those skilled in the art that
various modifications may be made to the illustrated embodiments
without departing from the scope as described in the specification
and defined in the appended claims.
* * * * *